In the printing of blanks for packing containers, for example, material webs of paper or cardboard are used which are wide enough for a number of package blanks to be arranged side by side. The printing of such a wide web naturally brings with it an increased capacity and improved economy. Because package blanks in particular frequently are provided with lugs and thus do not have a straight edge contour, it is necessary in order to avoid wastage to displace the blanks in relation to one another so that a minimum of wastage is obtained. Hence it is endeavoured to displace the blanks so in relation to one another that a projecting lug from one blank fits into a corresponding recess in the adjoining blank and, since the blanks are identical, it is often possible by mutual displacement of the blank placements to achieve a production of blanks completely free of wastage or, in any case, presenting a minimum of wastage. This implies though, that the printing plates for printing of the blanks have to be displaced in relation to one another as the print has to be adapted to the placing of the blank.
This problem has been solved previously in such a manner that a number of separate printing plates were mounted on a carrier cylinder with a mutual displacement corresponding to the desired displacement of the pattern on the printed web. This printing plate mounting work is very demanding and time-consuming, since the individual printing plates have to be placed with very great precision in relation to one another which, among other things, requires exceptional professional skill in the person carrying out the mounting of the printing plates on the carrier cylinder. This procedure also has given rise to large quantities of material having to be rejected because of insufficient precision in the mounting of the printing plates. The present invention proposes a method to avoid these difficulties and is characterised in that the printing plate is made in one piece with a width which corresponds to the combined width of the individual printing patterns, and that the printing plate is provided along both its front and rear edges with a stepped edge cutting so as to form a number of substantially rectangular coherent parts, each having a length corresponding to, or slightly exceeding, the length of a printing pattern. The invention is also characterized by a printing cylinder comprising a carrier cylinder, each of the said printing plate parts being arranged around and surrounding the carrier cylinder, the front edge of the printing plate parts being accommodated in a holding device arranged inside the contour of the carrier cylinder this holding device presenting a plane top side which is located level with the surface of the carrier cylinder and that the rear edge of the printing plate parts is fixed to the plane top side of said holding device.